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Invertebrate Zoology

03/30/2016

Wild animals that are directly visible in their environment are the main attraction for nature lovers. Most people do not know about the existence of a fascinating hidden world of animals that inhabit marine sand. This sand can host an impressive abundance and diversity of microscopic animals known as “meiofauna.”

These meiofauna are not only a key part of life's food chain and fundamental to keeping sediment clean, but they can also be used to address important questions in evolutionary ecology. For instance, how and why are there so many diverse species on Earth? How do they evolve in relation to time and different ecological conditions? How do geographical and geological barriers affect gene flow among populations?

Collecting sediments for meiofauna along the coasts of Azuero Peninsula and Iguana Island, Panama. Photo by Ulf Jondelius

These questions can potentially be answered by investigating the genomic diversity present in a small quantity of sand. Genotypes are correlated to the ecological conditions and geological histories of the environment. They can be used to infer the evolutionary origin of the group, and to infer how these organisms relate to each other; they are important to consider in existing general models of evolutionary ecology. Unfortunately, the genomes of meiofauna are poorly known. Our lack of knowledge is mostly because it is very difficult to identify these animals. It requires trained taxonomists spending several hours sitting at the microscope.

Some representative meiofauna. From upper left: an annelid, a nemertean, a gastrotrich, and the anterior part of a nematode. In the bottom, from left, a mollusk, platyhelminths Proseriata and Rhabdocoela, and a xenacoelomorph. Photos by: Freya Goetz (Annelida, Nemertea, Platyhelminthes), Ulf Jondelius (Xenacoelomorpha), Antonio Todaro (Gastrotricha), Alberto de Jesus Navarrete (Nematoda), Katharina Jörger (Mollusca).

I am Francesca, a Buck Global Genome Initiative (GGI) fellow interested in investigating the genomes of meiofauna and how their levels of diversity change through time. I aim to compare the genomes of species that have been separated by known geological events, such as the raising of the Panama Isthmus, and identify genetic markers that reflect environmental changes.

Working on very tiny animals, which also lack published genomes, is very tough. I spent part of my research learning genomics techniques and data analysis at Hubbard Center of Genome Studies at the University of New Hampshire, in Durham, under the guidance of Prof. W. Kelley Thomas and his staff. The collaboration among different research groups is always inspiring and exciting. Despite the challenges these organisms pose, we succeeded in retrieving the genomes of several species from the phyla Annelida, Nematoda, and Nemertea.

Our preliminary and exciting results encouraged me to increase the number of species I will look at and the number of places I hope to find them, as well as to increase our knowledge about the genomic information of these microscopic organisms. With these goals in mind, I organized an international workshop in Panama by inviting several specialists from Europe, South and Central America, and the US to collect, identify, and preserve meiofauna.

We focused on the still unexplored Pacific side of Panama, namely Azuero Peninsula and Iguana Island, sampling from 0 to 20 meters depth. The meiofauna laboratory was located at the Achotines Lab facility. About 2,000 specimens belonging to at least 10 phyla, tens of families, and hundreds of morphological species were collected. A digital image was made from each one, and they are now stored at the NMNH Biorepository with the aim to preserve and investigate their genomes. The workshop, funded by 2015 GGI Awards, was very successful in increasing the knowledge of this hidden and important ecosystem and preserving their genomes for future fundamental evolutionary ecological questions.

03/16/2016

When you look around you might notice birds going about their daily business. But what are they up to?

American redstarts are migratory birds that travel to Jamaica during the winter and potentially compete with resident birds, like the Yellow Warbler, for food. Photo by Dave Inman. CC By-NC-ND 2.0

It’s likely that they are foraging—looking for something to eat. Perhaps you’ve never thought much about what birds eat, but there’s a lot more to it than just worms, as the popular expression suggests. Many birds are insectivorous, meaning that they eat arthropods, a broader taxonomic group that includes insects and spiders (among other invertebrates).

As part of a Smithsonian sponsored project, I am collaborating with Luke L. Powell and Peter P. Marra of the Migratory Bird Center, Robert C. Fleischer of the Center for Conservation and Evolutionary Genetics, and Delano S. Lewis at Northern Caribbean University in Mandeville, Jamaica, to investigate the diets of insectivorous birds, as well as the poorly known but amazingly diverse community of Jamaican arthropods.

Our goal is to understand diet competition among resident Caribbean birds, and the millions of other birds that migrate to the Caribbean each winter. Specifically, we are studying two species, the yellow warbler (Setophaga petechia) and the American redstart (Setophaga ruticilla), at a long-term ecological research site at Font Hill Nature Preserve, Jamaica. In order to do this we are using cutting-edge, next-generation sequencing technology to sequence part of a gene (cytochrome oxidase I) of all arthropod diet items that have passed through the bird digestive tract and are excreted in their feces. We sequence all of the arthropods in the feces simultaneously, using a recently developed approach known as metabarcoding. We can then match the DNA sequences we obtain back to those of the arthropods living in the area, and figure out what the birds are actually eating.

Luke Powell using an aspirator to collect tiny beetles that have fallen onto a white shower curtain after vigorously shaking forest vegetation. Photo by Andreanna Welch

The little that we know about Jamaican arthropods suggests that they are very diverse. For example, even though Jamaica is 1/10 the size of Cuba and 1/7 the size of Hispaniola, the island has 20 species of jumping spiders, 45 species of fireflies, 20 species of butterflies and 6 species of ants that are found nowhere else in the world. However, Jamaican arthropods in general have not been studied extensively, and there are very few DNA sequences available in online databases, such as the Barcode of Life database, to which we could match the diet item sequences.

Delano Lewis, a Jamaican entomologist, uses the sweep net to sample arthropods from higher up in the forest canopy. Photo by Luke Powell.

The goal of our GGI funded project is to survey Jamaican arthropods in the Font Hill Nature Preserve to create a set of arthropod museum vouchers, collect genomic-quality samples, and obtain DNA barcode sequences for each species that we collect.

Black-light trapping a diverse array of moths, beetles, and other species. Photo by Luke Powell.

This will be important for understanding the biodiversity of the arthropod community there, and providing a baseline for future studies on the impacts of humans and global climate change. The information and samples collected during our study will also be an important resource for entomologists examining the evolutionary relationships of arthropods in Jamaica and elsewhere in the world. Beyond all this, the DNA sequences we obtain will help us to gain a better understanding of how bird species with similar diets are able to co-exist during the winter, which is one of the most food-limited times of year.

By Andreanna J. Welch, Research Associate at the Center for Conservation and Evolutionary Genetics in the Smithsonian Conservation Biology Institute (edited by GGI Staff).

03/03/2016

There’s more to reefs than fishes and coral, far more. In fact, it is estimated fishes and coral make up less than 1% of all reef-associated animal species. The other 99% of reef diversity – what is known as the cryptobiota – live within the reef matrix and play a critical role in reef functioning.

Not to be confused with yetis, bigfoot, or the Loch Ness Monster, crytopbiota are generally small, often tiny, and largely understudied. They contain members from across almost all branches of the tree of life. This hidden component lies among the nooks and crannies, and is what I aim to document as a research zoologist here at NMNH.

One way to get at these cryptic communities is through the use of Autonomous Reef Monitoring Structures (ARMS). ARMS are constructed as standard units, consisting of a stack of 9 PVC plates that mimic the complexity of the reef. Like pre-fabricated homes, these units are deployed for a period of time, recovered and analyzed to see who has moved in. Because they are standardized, ARMS can be compared around the world and over time to measure patterns and changes in marine biodiversity.

ARMS have become the standard for reef biodiversity monitoring across the marine world, especially for marine community members that are hard to quantify. More than 1200 ARMS have been deployed at more than 100 sites worldwide, with the installations in Costa Rica being the first in the tropical Eastern Pacific. Map credit – Smithsonian Global ARMS Program.

Recently, the Global Genome Initiative (GGI) provided funding for ARMS to be deployed at three sites in the Islas Murciélagos, in Sector Marino of the Area de Conservacion Guanacaste (ACG), off the Pacific Coast of northwestern Costa Rica. These are the first installations of ARMS in the tropical Eastern Pacific. GGI is a collaborative endeavor to collect the Earth’s genomic biodiversity, preserve it in the world’s biorepositories, and make it available to researchers everywhere. This project enables us to work strategically towards that goal by focusing on the collection, processing, and preservation of genomic material from poorly known – yet extremely diverse – communities.

A view from above the research station overlooking the Bay of Isla San Jose where three of the ARMS are deployed. Photo: Chris Meyer

After a year, we will collect the deployed ARMS and bring them back to the lab to sample them for biodiversity. The ARMS plates are disassembled plate-by-plate and photographed for spatial analyses. Motile specimens are sorted through different sized sieves; those larger than 2 mm are further sorted into taxonomic groups, which are then processed as standard voucher-based specimens and DNA barcoded. Similarly, representative vouchers are sampled from sessile specimens to build a comparable reference library of species.

Once vouchers are taken, the plates are scraped clean and the resulting material is homogenized in a blender and preserved for DNA analyses. These sessile communities, and smaller motile fractions (< 2 mm), are analyzed all together using an advanced “next-generation sequencing" method called metabarcoding to get diversity profiles from each fraction. A portion of the samples is processed right away, while others are stored in the NMNH's Biorepository for future genomic research.

One of the ARMS sites is near the local research station in the Bay of Isla San Jose, so it can be easily monitored as it accumulates species and can be shown easily to visitors and students at the station.

During the ARMS recoveries, along with our Costa Rican colleagues, we will be training "parataxonomists" who are local individuals interested in biodiversity studies, but have little taxonomic expertise in many of the marine groups. We use the ARMS and resulting specimens for first-hand taxonomic training about the cryptobiotic community . We are teaching the parataxonomists how to deploy and recover ARMS, so they can address their own questions in the future.

Pedro Bank is located 60 nautical miles southwest of Kingston, Jamaica and is the Caribbean's main fishing ground for spiny lobster and queen conch in this area. Almost all the spiny lobster harvested in Pedro Bank is consumed in the United States, while most of the queen conch is exported to the French Caribbean territories of Guadeloupe and Martinique. The lobster and conch fisheries in Jamaica generate several million US dollars per year and provides a crucial source of employment for artisanal fishers (fishermen and fisherwomen) living in remote coastal communities.

Not all of Pedro Bank is open for fishing. The Southwest Cayfish Sanctuary, located in Pedro Bank, is Jamaica’s first offshore marine protected area (areas protected for conservation purposes, like Bird Cay – the uninhabited seabird sanctuary).

We discussed our research with artisanal fishers on Pedro Bank, who helped Dr. Courtney Cox and I collect genetic samples for our research.

Pedro Bank has three small sandy cays located on the southwestern edge of the bank. Fishers inhabit two of the cays and the third, Bird Cay, is an uninhabited seabird sanctuary where fishing is not allowed. Middle Cay is home to approximately 500 artisanal fishers who spend up to 11 months a year on the cay. Though the Jamaican Defense Force Coast Guard conducts routine patrols of the waters of Pedro Bank to catch lobster and conch poachers, still up to one third of all the lobster and conch harvested in Pedro Bank are illegally poached by foreign commercial fishing boats then exported with a false origin of catch to cover their tracks.

With the samples I collected, I am now at Stanford’s Hopkins Marine Station where I’m collaborating with Dr. Stephen Palumbi’s lab to develop DNA-based traceability tools for spiny lobster and queen conch, with the hopes of helping regulate and prevent illegal harvesting of these key commercial species in the Caribbean.

12/08/2015

Everyone knows that a caterpillar will change into a butterfly and tadpole will become a frog, but did you know that marine sponges undergo metamorphosis too?

I am Rachel Collin, the director of the Bocas del Toro Research Station in Bocas del Toro, Panama, which is a part of the Smithsonian Tropical Research Institute. I study the reproduction and larval development of marine invertebrates (i.e. crabs, snails, or any marine organism without a backbone). This covers what sexes the animals are, how they mate or if they mate, how the eggs develop into juveniles, and how larvae develop into adults.

Adult marine sponges develop from larvae, similar to the way a caterpillar metamorphoses into a butterfly. Likewise, the adult sponge and its larva look nothing alike and they act differently. For example, sponge larvae actively swim around and adult sponges can't move.

By studying the genetics of these organisms, it can help us to understand how one genome can produce these two completely different kinds of life stages.

Specifically this project, sponsored by NMNH's Global Genome Initiative, will look at the differences in what genes are used in the larva versus the adult sponge. We hope to get a little closer to understanding how the same genes can be used to make these different life stages. We also hope to understand how the microbial community (or microbiome) changes across the life cycle and what impact that has on the sponge.

Rachel Collin—At work in the lab.I always wanted to be a scientist and always had an interest in marine invertebrates, from my very first visit to the beach and intertidal when I was a child. I first got interested in invertebrate reproduction and development when I worked at the Friday Harbor Labs in Puget Sound for my Master's degree. I'm attracted to the diversity of different strategies animals use. It's amazing to me that some animals change sex; some inject sperm into the body cavities of their mates; some don't even need a mate to reproduce. And the larvae of different animals are so diverse and beautiful, it's hard not to want to know how they live.

Understanding these sponges is much more than just an academic interest. Marine sponges are globally distributed and perform important ecological roles in all the ecosystems they are found. They also support diverse ecosystems both as a substrate as well as hosting a diverse microbiome. The sponge microbiome is more diverse that any other invertebrate; the amount of diversity is similar to the of microbiomes associate in our guts.

Few studies have explored the functional roles of microbial symbionts in distinct life-history stages. I hope our current GGI project will help us fill in this critical gap.

By Rachel Collin, Director of the Bocas del Toro Research Station, Smithsonian Tropical Research Institute, Panama (edited by GGI Staff).

11/24/2015

How do you endure the cold winters of DC? Go to Baja California! In February of 2015, I escaped the icy rain of DC to meet colleagues and their ships down in sunny Baja California, Mexico. I worked with the Midwater Ecology group, from the Monterey Bay Aquarium Research Institute (MBARI), led by senior scientist Bruce Robison. Their objective was to better understand the oxygen minimum zone in the southern basins of the Gulf of California and its influence on the ecology and physiology of midwater fauna. I study these animals at the National Museum of Natural History (NMNH).

Karen Osborn and the new mini-Rover on deck of the ship in the sunny Gulf of California, Mexico examining her new catch. Photo by Susan Von Thun

We were using the large remotely operated vehicle (ROV) Doc Ricketts, named after the famous Ed Ricketts, marine biologist that inspired the well known writer John Steinbeck. We also used a midwater trawl net and a new mini-ROV to observe and sample the water between 50–3200 meter depth (165–10,500 feet). The midwater is the largest habitat on earth—all the water between the sea surface and the ocean floor—it regulates our climate, absorbs our carbon dioxide, and houses billions of organisms throughout its entire depth, from viruses and bacteria to shrimps, jellies, squid and fish. I was collecting a wide diversity of hyperiid amphipods (cousins of those tiny beach hoppers that you see spring away from you as you walk along the beach), polychaete worms (the often beautiful cousins of earthworms) and acorn worms. I study the way these animals adapt to the midwater habitat where life is very different from anything we can relate to, or any these animals ancestors were adapted to.

Two hypriids and a cydippid comb jelly exhibit typical midwater adaptations for survival in the midwater - unusually large and complex eyes, huge grasping hooks used to hang onto prey, and a transparent body. Each gives the bearer some advantage that helps it survive this alien environment. Photos by Karen Osborn

On this trip, I collected specimens for my own research and genomic samples for the NMNH's Global Genome Initiative. For each animal collected I would identify it, describe it in as much detail as possible, photograph it, anesthetize it, take a tissue sample in chilled 95% ethanol, and take a sub-sample of tissue directly into extraction buffer for immediate sequencing upon return. The rest of the animal was preserved as the morphological voucher. I collected specimens and tissues from representatives of 5 phyla, 38 families, and 54 genera, so it was a very successful trip.

As in terrestrial habitats, the majority of the animals found are quite small, like the beautiful red Prohyperia (amphipod) shown here. However, we also regularly see the longest animal on earth—Praya, which is a siphonophore that can reach 150 feet long (sorry, no pictures of that one). The Prohyperia above is still clinging to its host, the deep red scyphomedusa Nausithoe. We are looking under the bell at one of the three hypriids found living on this individual jelly. Photo by Karen Osborn

I decided to become a marine invertebrate biologist while teaching high school and diving in Pohnpei, Micronesia as a college student. Now as a marine biologist, I hope to obtain a better understanding of the midwater—how it functions, key players in the communities that thrive there, and how the animals there have changed through time to meet the unique challenges of the habitat. Also, I would like to increase awareness of this important habitat and consideration of it in our daily decisions about our planet.

Dr. Osborn on board the research vessel Western Flyer in the Gulf of California, Mexico, examining specimens from the catch. Photo by Susan Von Thun

By Karen J. Osborn, Research Zoologist in Invertebrate Zoology, at the National Museum of Natural History.

11/10/2015

For ten days this summer, I woke up more than 20 nautical miles from land during an expedition to a remote part of the Caribbean Ocean. Each day, I saw nothing but turquoise water and a pale blue sky, not a bird or tree in sight. Trips like this to the open ocean are what I love to do.

View from the bow of the Shedd Aquarium’s RV Coral Reef II, on location near the Bahamas. Photo by Vanessa L. Gonzalez.

As the research bioinformatician for the Global Genome Initiative, I had the pleasure of joining this trip to assist in the collection of two commercially and ecologically important coral reef species: the Caribbean spiny lobster and queen conch.

While many people think of these species as tasty delicacies, both of these creatures play an important role in maintaining the heath of their ecosystem. Yet, they are currently under extreme threat from over fishing.

By understanding the genetic dynamics of these creatures, scientists can better assess their ability to respond to fishing pressures and environmental changes. And while the need for genomic sequencing of these animals is clear, obtaining these samples is no easy task.

You might think a conch found only a few meters away from another would be similar genetically, but that is not always true. Populations can be vastly different genetically even though they are neighbors. The exact opposite can also be true, populations can have the exact same genetic structure and be located in completely different regions of the ocean.

Our work was part of a Smithsonian Institute for Biodiversity Genomics and Global Genome Initiative sponsored project that aims to understand how species adapt to their unique marine environments. Specifically, this study—led by Smithsonian scientist Dr. Stephen Box and Dr. Nathan K. Truelove, along with Stanford University’s Dr. Stephen R. Palumbi—seeks to understand the genomic make-up of the spiny lobster and queen conch to look at the genetic variation across the Caribbean.

Ultimately, the genomic resources developed by this project have the potential to improve the sustainable management of the lobster and queen conch in the Caribbean. Through the generation of DNA databases, we can potentially provide valuable tools for combating illegal and unreported fishing throughout the region. As a result of this study, the information from the DNA databases could open up the possibility of tracing a catch back to where it was originally caught; similar to the way the police might use a forensic database.

After 10 nights of being rocked to sleep by unrelenting 7 foot swells, we emerged in Miami, FL with dozens of tissue samples floating in a tank of liquid nitrogen. This is just one of 10 expeditions to collect these species. These samples will be preserved in perpetuity in the Smithsonian’s Biorepository helping us understand the interconnectivity in the ocean, and protect these two important species.

Dr. Vanessa L. Gonzalez, on one of many expeditions, this time while SCUBA diving on for a separate project in Spain. Photo by Gonzalo Giribet.

By Vanessa L. Gonzalez, Research Bioinformatician of the Global Genome Initiative, Smithsonian Institution, National Museum of Natural History.

08/14/2015

In June of this year, the Smithsonian's Global Genome Initiative (GGI) sponsored an expedition to Myanmar to preserve genomes of its fauna. Below is a story by one of our researchers!

Boiga dendrophila (Boie 1827). Mangrove snake. The large, impressive, mildly venomous snakes can reach over two meters in length. They are mostly arboreal (living up in the trees), but come down to the streams at night. Four individuals (each approximately 2 meters) were observed on this expedition. Lenya National Park, Tanintharyi Division, Myanmar. Photo by Daniel G. Mulcahy (GGI staff).

My work involves collecting venomous snakes, and on my most recent trip we also collected tarantula's and other spiders, scorpions, and a foot-long centipede, which you do not want to bite you.

I am Dan Mulcahy, I have a bachelor’s degree in Integrative Biology, with an emphasis on Vertebrate Zoology. I have a PhD in Evolutionary Biology, and I currently work at the National Museum of Natural History's (NMNH) Global Genome Initiative (GGI). I study natural history, biogeography, taxonomy, and speciation of amphibians and reptiles. In the last two years, I have conducted biodiversity surveys in Myanmar, and I really enjoy that because it's different, new to me, and one of the more "un-explored" places on Earth.

Daniel G. Mulcahy (GGI staff), walking out of a disturbed forest area in the Lenya National Park, Myanmar. The area here is being deforested and converted to plantations. Photo by Bonnie B. Blaimer (NMNH Postdoc in Entomology).

Conservation of life on earth—I study these animals because I like them, but they are disappearing fast. Many species are becoming extinct before we can properly describe them, a phenomenon now known as "forensic taxonomy" (see also one of my articles in Zootaxa 2396). Species are often disappearing before we know their geographic distribution, or understand their roles in their ecological community. I would hope that my work helps to achieve a better understanding about these organisms and ultimately contributes to help conserve them. So much habitat is disappearing so rapidly around the world, from agriculture, to mining, logging, and human development. I think it is important to educate the public on environmental issues and evolutionary biology. But what is really necessary is for people to understand that biodiversity on this planet is extremely diverse, interesting, fascinating, and ultimately, worth saving.

We conducted biodiversity surveys in Myanmar, in collaboration with Fauna and Flora International (FFI), a conservation group with an office in Yangon, Myanmar. A major project of FFI in Myanmar is to inventory the biota (fauna and flora) of areas proposed or designated as national parks in the Tanintharyi Division, the southern-most part of Myanmar, located on the Malaysian Peninsula. We assisted FFI with their biodiversity surveys by providing taxonomic expertise, and with additional funding from a Global Genome Initiative grant, secured genome-quality tissues to be stored at the Smithsonian Institution's Biorepository.

Due to the remoteness of this region, we were not able to obtain liquid nitrogen to flash-freeze our samples (the preferred method). Therefore, we used different ambient-temperature solutions for storing our genomic materials for later comparisons.

Oecophylla smaragdina (Fabricius 1775) Weaver ants. A group of arboreal weaver ants take on a carpenter ant, genus Camponotus, and carry their prey back to through the leaf litter to their nest. Lenya National Park, Southern Tanintharyi region, Myanmar. Photo by Bonnie Blaimer (NHMH Postdoc in Entomology).

Our efforts were focused on three major taxonomic groups: amphibians and reptiles (myself), insects (Bonnie B. Blaimer, an NHMH Postdoc in Entomology), and terrestrial and freshwater invertebrates (John D. Slapcinsky, a Senior Biologist at the Florida Museum of Natural History). We conducted visual encounter surveys, both day and night, on trails, streams, and in limestone caves. We also conducted leaf-litter sampling, set Malaise traps (for diurnal flying insects), and used black-lights (for nocturnal flying insects) for insects and other invertebrates.

Rhacophorus sp. Kuhl and Van Hasselt, 1822. Black-webbed Treefrog. These frogs can glide from tree to tree in the canopy, and are thus often refered to as "flying (or gliding) frogs." Lenya National Park, Tanintharyi Division, Myanmar. Photo by Daniel G. Mulcahy (GGI staff).

We surveyed two areas over the course of 17 days, in Lenya National Park and a proposed extension area, both near the border with Thailand. These areas are currently vulnerable to logging, mining, agriculture, and over-harvesting of endangered animals by local hunters. Preliminary estimates from our surveys indicate that we sampled: 2 classes, 3 orders, 14 families, 38 genera, and over 60 species of amphibians and reptiles; 12 orders, and over 300 species of insects, and 5 phyla, 8 classes, 15 orders, 32 families, and likely over 500 species of other invertebrates.

Our teams are now in the process of confirming field identifications, assessing the quality of the genomic material, and conducting DNA barcoding analyses. We will then provide FFI with detailed reports of our findings, so that our efforts will contribute to documenting the biodiversity of this region and assist in conservation management strategies.

Ptychozoon lionotum (Annandale 1905). Burmese Flying (or Parachute) Gecko. These geckos glide (or “parachute”) between trees using flaps of skin along their bodies, arms, head, extensively webbed feet, and a wide, flat tail. The flaps of skin are folded under during rest. They are primarily nocturnal (active at night) and have excellent camouflage, as shown here on bark from the same tree on which it was found. This specimen has a regenerated tail. They prefer dense, primary forest habitat. Lenya National Park, Tanintharyi Division, Myanmar. Photo by Daniel G. Mulcahy (GGI staff).

Ma Noe Lone, a tributary to the Lenya River, in Lenya National Park, Tanintharyi Division, Myanmar. The area is mixed evergreen forest, dominated by bamboo. The water level is relatively high here because of recent heavy rains. Photo by Bonnie B. Blaimer (NMNH Postdoc in Entomology).

By Daniel G. Mulcahy, staff of the Global Genome Initiative, Smithsonian Institution, National Museum of Natural History.

06/27/2015

The United Nations establishes international days to promote awareness on global issues and to commemorate important events. Other groups declare a day for much less serious reasons, for example, the delicious Strawberry Shortcake Day or the playful Go Fly a Kite Day. Depending on the calendar, there is a “Day” for nearly everything you can imagine, except …..polychaetes.

Polychaetes are segmented worms (I heard those eews!) that are found mostly in saltwater. There are about 8,000 named species in the world and at least twice that many still to be named. They are very important animals in the food webs that are critical to keeping our oceans healthy --- many are even breathtakingly beautiful.

Polychaetes are found in all marine habitats from the deepest oceans to the shallowest tide pool, and even in freshwater habitats. They are often the most numerous animals in a square meter of sea floor mud. They range in size from less than a millimeter as adults to several meters long. They are found in the fossil record back through the Cambrian. They build reefs from their tubes, turn over the seafloor much like their earthworm cousins, and are a major part of marine food webs. Most have hydrostatic skeleton, which means instead of their muscles working on hard structures like bone or cartilage, they work on pressure from water – think about a water balloon pushing and pulling against that constricted water. Bottom line, they are essential and fascinating members of our world.

Serpula uschakovi, a serpulid polychaete. Photo by Alexander Semenov.

So, if Gummy Worms get a day, we decided it was time that polychaetes get one too. We chose to commemorate a great polychaete scientist, Kristian Fauchald, a dedicated scientist who spent 36 years at the Smithsonian. Kristian passed away in April, and we decided to commemorate him on what would have been his 80th birthday – July 1, 2015.

Our goal is to share the beauty, interest, and importance of polychaetes with the world on this day in honor of Kristian. To do that, we are encouraging a global conversation with a large network of activities and experts talking to the public at museums, aquaria, and science education centers around the world.

04/28/2015

Paulasterias tyleri feeding on deep-sea barnacles. Image courtesy of the British Antarctic Survey.

I am Dr. Christopher Mah, a Research Collaborator in the Department of Invertebrate Zoology and my title is a descriptor of what I do! My research focuses on the diversity and evolution of sea stars, which most people are probably most familiar with as star-shaped inhabitants of beaches and intertidal zones. What most people don’t realize is that sea stars occur at all depths, some live in depths of over 8000 meters! By comparison, the deepest point of the Grand Canyon is only about 1800 meters (6000 feet). It also surprises many people that sea stars occur in environments which are very inhospitable to humans. A great diversity of sea stars can be found in the Southern Ocean (Antarctica), some living in only a few meters of water but others occur thousands of meters below the ice-covered ocean surface. So, that’s a double-whammy: Antarctic AND deep-sea!!

One of the museum’s core strengths is that of partnership, collaboration with other organizations both in the United States and abroad. It’s not unusual for some of the most important discoveries to result from collaboration with MANY other scientific institutions!

An expedition undertaken by the British Antarctic Survey (BAS) in 2012 discovered that hydrothermal vents were present at approximately 2,400 meters depth on the seafloor of the Scotia Arc region in Antarctica. These are regions where toxic chemicals, such as hydrogen sulfide, bubble out of geothermal/volcanic openings on the bottom of the ocean. Surprisingly, an array of unique animals survive and thrive in these hostile environments. Among the most surprising of discoveries from this region was an enigmatic 7-rayed sea star which biologists and geologists observed feeding on the crustaceans living amidst the hydrothermal vents!

Paulasterias tyleri (about 2 inches in diameter) has been observed feeding on the barnacles and the “hoff crabs” which also live in the vent system. P. tyleri can have 7-8 arms. Image by C.Mah.

My colleagues at the BAS contacted me in due time and sent me the specimens for study and analysis. At the same time I had just completed the 2009 Pacific Northwest expedition with the Monterey Bay Aquarium Research Institute (MBARI). We had been studying deep-sea geology and biology along the Juan de Fuca and Gorda mid-ocean ridges (adjacent to hydrothermal vents) in the deeps of the North Pacific Ocean and had just collected a mysterious new species of 6-rayed sea star which was widely present in the area, from 2200-3300 meters.

The second species discovered, Paulasterias mcclaini (about 1 inch in diameter), is named for deep-sea biologist Dr. Craig McClain at the NESCENT center at Duke University. Image by C. Mah.

Molecular analysis of these two, seemingly independent, specimens revealed a surprising result: they were closely related to one another! Additionally, they emerged on an evolutionary lineage independent of other closely related sea stars. Further work analyzing their body form, using features viewed with our scanning electron microscope (SEM), clarified the relationship between these two new species.

P. tyleri has seven arms, a very soft body wall and distinctive structures known as pedicellariae, which resemble jaws, seen in the SEM image above. Image by C. Mah & Bob Ford.

Two NEW species from very different locales at bathyal depths of the ocean: the Antarctic and the North Pacific, which analysis has further revealed to be members of a NEW family! Paulasteriidae is the new family, which includes two species: Paulasterias tyleri and Paulasterias mcclaini. This is one of the first new families to be described since 2002! Very disparate pieces of a deep-sea puzzle have been brought together by study at the museum through efforts from teams on two continents and about five different institutions! I was happy to have named the species/genus/family of these animals but I am especially grateful that so many scientists have been so cooperative and worked so hard to make such a project successful!